[plt-scheme] science fair help

(check-expect (average (list (list 1 3 5 7) (list 2 1 3 3) (list 3 8 1 5)))
              (list 2 4 3 5))
              
(define (average lol)
  (map (lambda (a b c) (/ (+ a b c) 3)) (first lol) (second lol) (third lol)))


yields 

> Welcome to DrScheme, version 4.2.3.4-svn4dec2009 [3m].
> Language: Intermediate Student with lambda.
> The test passed!
> >

So what's the problem? -- Matthias



On Dec 13, 2009, at 8:02 PM, Todd O'Bryan wrote:

> I have a student who's doing a science fair project and needs to find
> the average for each location in a bunch (number unspecified) of
> lists.
> 
> For example, given
> 
> (list 1 3 5 7) (list 2 1 3 3) (list 3 8 1 5)
> 
> he'd like
> 
> (list 2 4 3 5)
> 
> I can write the function pretty easily in Module by writing an average
> function that takes a variable number of arguments, but my attempts to
> do it in Intermediate or Advanced are pretty complicated. Is there a
> fairly easy way to do it in the teaching languages that I'm missing?
> If not, I can just put together a teachpack for him that provides that
> function so he can use it.
> 
> Todd
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